code: def add_cmdline_args(
      cls, parser: ParlaiParser, partial_opt: Optional[Opt] = None
  ) -> ParlaiParser:
      group = parser.add_argument_group("FixedResponse Arguments")
      group.add_argument(
          "-fr",
          "--fixed-response",
          type="nonestr",
          default="I don't know.",
          help="fixed response the agent always returns",
      )
      return parser
  
file_path: ParlAI/parlai/agents/fixed_response/fixed_response.py
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.core.agents import Agent
  from parlai.core.message import Message
label_desc: Use image node_id 1 for calling the FixedResponseAgent obj's underlying member method code with example usage: obj.add_cmdline_args(cls, parser, partial_opt) and returns: parser